Question: $ { \left[\begin{array}{rr}{-2} & {0} \\ {1} & {-1} \\ {3} & {3}\end{array}\right]+\left[\begin{array}{rr}{3} & {4} \\ {0} & {0} \\ {-1} & {1}\end{array}\right] = {?} } $
Explanation: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rr}{-2}+{3} & {0}+{4} \\ {1}+{0} & {-1}+{0} \\ {3}+{-1} & {3}+{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{1} & {4} \\ {1} & {-1} \\ {2} & {4}\end{array}\right]}$